Groundwater recharge into the High Plains Aquifer on the Belvoir Ranch

The Belvoir Ranch is an area of 18,800 acres on the south side of Interstate-80 west of Cheyenne, WY and east of the Laramie Range. The High Plains Aquifer underlies the ranch and is comprised of the Ogallala and White River Formations. The city of Cheyenne is currently developing groundwater from the High Plains Aquifer on the ranch to supplement their municipal water supply. Proper management of the groundwater supply requires understanding of the hydrology. An essential component of the hydrology is groundwater recharge, defined as water replenished to the saturated subsurface. Groundwater recharge has not been addressed in this area since the 1940's. The objective of this study is to initiate an updated estimate on groundwater recharge on the Belvoir Ranch. Recharge was estimated using two methods: (1) monitoring water levels in 43 wells completed in the aquifer and (2) create a spatial, water mass-balance computer model for estimating annual recharge due to infiltration at the ground surface. The water levels provide both qualitative and quantitative information about groundwater recharge and system response. The mass-balance model, SWAT, provides a dynamic and quantitative estimate of recharge based on precipitation and provides upper and lower bounds of recharge at the study site.